Japanese Unexamined Patent Application Publication (JP-A) No. 2012-135845 discloses a screwdriver that rotationally drives a driver bit. In this screwdriver, a spindle that holds the driver bit is arranged to be movable in its longitudinal direction.
A clutch detecting mechanism detects engagement of a clutch which is caused by movement of the spindle and a control part controls driving of a driving motor based on the detection result.